[swift-dev] -whole-module-optimization with -Onone

[Ben Asher]

Sure! Thanks for reminding me. I'll follow up on that, test, and get back
to you.

Ben

On Thu, Dec 1, 2016 at 2:48 PM, Mark Lacey <mark_lacey at apple.com> wrote:

>
> On Dec 1, 2016, at 3:13 PM, Ben Asher via swift-dev <swift-dev at swift.org>
> wrote:
>
> Just running a quick trial before and after I made this change in our
> project, we were previously seeing builds of our main target that took just
> under 13min. With this hack, a clean debug build takes about 4.5min.
>
>
> You may find that recent snapshot builds from swift.org help with your
> build times even without enabling -Owholemodule. The redundant type
> checking of synthesized accessors which we talked about a month or two
> should now be fixed on master, and it would be great to verify that’s the
> case with your code and to get an idea of how much it improves your build
> times.
>
> Mark
>
>
> Ben
>
> On Thu, Dec 1, 2016 at 1:33 PM, Ben Asher <benasher44 at gmail.com> wrote:
>
>> Okay I think that worked! And just to clarify, you meant set
>> SWIFT_OPTIMIZATION_LEVEL = -Owholemodule and OTHER_SWIFT_FLAGS = -Onone ?
>>
>> I'll file a radar this afternoon with some details and DM you the number.
>>
>> Thanks again!
>>
>> Ben
>>
>> On Thu, Dec 1, 2016 at 1:10 PM, Jordan Rose <jordan_rose at apple.com> w
>> rote:
>>
>>> Xcode needs to know that you're building in WMO mode, so rather than
>>> putting -whole-module-optimization in your "Other Swift Flags", put -Onone
>>> there. It's an ugly hack but it should work in the near term.
>>>
>>> We do want to work to make this drastic speed difference go away, so if
>>> you're able we (at Apple) would love to have a source drop of your Swift 3
>>> project, for additional data on where the problems are. Mind filing a Radar?
>>>
>>> Best,
>>> Jordan
>>>
>>>
>>> > On Dec 1, 2016, at 11:51, Ben Asher via swift-dev <swift-dev at swift.org>
>>> wrote:
>>> >
>>> > Hello! Someone recently tipped me off to using
>>> -whole-module-optimization flag with -Onone for use during debug builds to
>>> speed up compile times. In our project, the speedup feels quite dramatic,
>>> but when it gets to the linking step (after compiling both Swift and Obj-C
>>> in the project) it fails because ld can't find the individual object files
>>> that normally get emitted during the debug-type build presumably because
>>> -whole-module-optimization only emits one (and this isn't a normal
>>> "-Owholemodule"-type build which works fine).
>>> >
>>> > I can't seem to reproduce this outside of Xcode, but I was curious if
>>> anyone has tried this and knows of a workaround to get
>>> -whole-module-optimization to work with -Onone in Xcode?
>>> >
>>> > I'm currently using Xcode 8.1 (App Store build) and Swift 3 on macOS
>>> Sierra.
>>> >
>>> > Thanks!
>>> >
>>> > Ben
>>> > _______________________________________________
>>> > swift-dev mailing list
>>> > swift-dev at swift.org
>>> > https://lists.swift.org/mailman/listinfo/swift-dev
>>>
>>>
>>
>>
>> --
>> Ben
>>
>
>
>
> --
> Ben
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>
>


-- 
Ben
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